11 
Animal and fungus injury were next searched for. The former 
was observed in some variety. The workings of the carrot fly 
larvae were manifest both in field and garden crops. Slug-injury 
was also noted, and the occasional presence of wireworms and 
surface caterpillars (Agrotidae), locally termed “‘ leather grubs,” 
doubtless accounted for other damage. The millipede (Julus pul- 
chellus) was often abundant in the decaying parts. se 
animals, however, were far too few in number and too irregular in 
distribution to be for a moment considered as being primarily re- 
sponsible for canker. Carrot fly was the most general, but it was 
usually sparsely distributed except in small gardens and allot- 
ments, and the characteristic tunnellings which the larvae pro- 
duce, not ouly on the shoulder but in all parts of the outer tissue 
of the root, form a very definite and distinct type of injury. 
Cause of Canker.—The cause of canker was more satisfactorily 
ceasing to search for all indirect and subsidiary causes, wa e 
the subject of special investigation during the remainder of the 
visit. ‘The cracks were, as a rule, } to 2 in. long a 5-3 in. 
The fresh wounds were perfectly clean (Plate iv, figs. 1 and 2), 
but the cortical tissue within soon became attacked by animals, 
such as slugs and centipedes, and by various fungi and other 
The cracks were obviously due to the expan- 
as a result of other wounds, such as carrot-fly injury is possible 
and even probable, but it was obvious that a very large propor- 
tion of the trouble in Worcestershire is, primarily, due to this 
the periderm. The cause of crack-formation and 
the inner tissues is discussed later. 
canker originated from these surface lesions. That it may follow 
rupture of 
subsequent decay of 
Experiments at Kew.—Although the origin of the canker had 
been traced to the surface lesions described above, the organisms 
‘eoncerned with the actual decay had not been classified and 
